DE102022101923A1 - stator - Google Patents

Abstract

The invention relates to a stator (1) for an electrical machine, comprising a stator body (3) which is formed from a plurality of stator laminations (4) arranged in layers, and the stator body (3) has a plurality of fluid channels (5) which through which a cooling fluid (6) can flow, and an A end shield (7) and a B end shield (8), which are each arranged on the end face and on opposite end faces (9) of the stator body (3), the A end shield ( 7) and/or the B end shield (8) and/or the stator body (3) have/have at least one hydraulic connection (10), by means of which the cooling fluid (6) flows through the A end shield (7) and/or the B - The end shield (8) and/or the stator body (3) can be guided to at least one of the fluid channels (5), the stator body (3) having a first group of stator laminations (11) which have a plurality of them essentially in the axial direction fluid channels (12) extending through the stator body (3), and a second group of stator laminations (13) which has a plurality of connecting channels (14) extending essentially in the circumferential direction through the stator body (3), by means of which two in the circumferential direction adjacent fluid channels (12) are fluidically coupled to one another.

Description

The present invention relates to a stator for an electrical machine, comprising a stator body, which is formed from a plurality of stator laminations arranged in layers, and the stator body has a plurality of fluid channels through which a cooling fluid can flow, as well as an A end shield and a B end shield, which are each arranged on the end face and on opposite end faces of the stator body, wherein the A end shield and/or the B end shield have/have at least one hydraulic connection, by means of which the Cooling fluid can be guided through the A end shield and/or the B end shield to at least one of the fluid channels.

Electric motors are increasingly being used to drive motor vehicles in order to create alternatives to internal combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability for everyday use of electric drives and also to be able to offer users the driving comfort they are accustomed to.

A detailed description of an electric drive can be found in an article in the ATZ magazine, volume 113, 05/2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrative and flexible electric drive unit for electric vehicles. This article describes a drive unit for an axle of a vehicle, which includes an electric motor that is arranged concentrically and coaxially with a bevel gear differential, with a switchable 2-speed planetary gear set being arranged in the power train between the electric motor and the bevel gear differential, which is also positioned coaxially with the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and allows a good compromise between climbing ability, acceleration and energy consumption due to the switchable 2-speed planetary gear set. Such drive units are also referred to as e-axles or electrically operable drive train.

In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains of a hybrid vehicle usually include a combination of an internal combustion engine and an electric motor, and allow - for example in urban areas - a purely electric mode of operation with simultaneous sufficient range and availability especially for cross-country trips. In addition, there is the possibility, in certain operating situations, to be driven simultaneously by the internal combustion engine and the electric motor.

In the development of electric machines intended for e-axles or hybrid modules, there is a continuing need to increase their power densities, so that the cooling of the electric machines required for this is becoming increasingly important. Due to the necessary cooling performance, hydraulic fluids, such as cooling oils, have prevailed in most concepts for dissipating heat from the thermally stressed areas of an electrical machine.

Jacket cooling and winding overhang cooling are known, for example, from the prior art for cooling electrical machines using hydraulic fluids. While jacket cooling transfers the heat generated on the outer surface of the stator laminations into a cooling circuit, with end winding cooling the heat transfer takes place directly on the conductors outside of the stator laminations in the area of the winding overhangs into the fluid.

Further improvements are offered by separate cooling ducts, which can be integrated into the laminated core of the stator (see e.g. EP3157138 A1 ) as well as in the slot in addition to the conductors (see e.g. Markus Schiefer: Indirect winding cooling of highly utilized permanently excited synchronous machines with tooth coil winding, dissertation, Karlsruhe Institute of Technology (KIT), 2017).

Increasingly, for reasons of weight saving, for example, electrical machines without a housing are also being used. In the case of such caseless electrical machines of high performance classes, it is generally necessary to actively cool the laminated cores. For this purpose, cooling channel courses are usually required which require a series and/or parallel connection of the cooling channels in the laminated core.

In order to realize this, components are placed at the inlets and/or outlets of the cooling channels, which control the deflection of the cooling fluid into the corresponding cooling channels. It is also possible that several components are required for the deflection. What these components have in common is that additional contours must be present for the deflection of the cooling fluid. Some of these contours are complex and therefore usually expensive to manufacture. Furthermore, such components for deflecting the cooling fluid can lead to a high pressure loss in the cooling circuit, which is regularly undesirable.

The object of the invention is therefore to avoid or at least mitigate the disadvantages known from the prior art, and to achieve a Sta provide tor, which for the formation of a series and / or parallel connection of fluid channels in the laminated core requires no additional components. It is also the object of the invention to realize a stator with a series and/or parallel connection of fluid channels in the laminated core, the pressure loss of which is as low as possible and at the same time ensures the highest possible heat transfer.

This object is achieved by a stator for an electrical machine, comprising a stator body, which is formed from a plurality of stator laminations arranged in layers, and the stator body has a plurality of fluid channels through which a cooling fluid can flow, and an A end shield and a B end shield, which are each arranged on the end face and on opposite end faces of the stator body, the A end shield and/or the B end shield and/or the stator body having at least one hydraulic connection /has, by means of which the cooling fluid can be guided through the A end shield and/or the B end shield and/or the stator body to at least one of the fluid ducts, the stator body having a first group of stator laminations, which has a plurality of fluid ducts extending essentially in the axial direction through the stator body, and a second group of stator laminations, which has a plurality of connecting ducts extending essentially in the circumferential direction through the stator body, by means of which two connecting channels in the circumferential direction adjacent fluid channels are fluidically coupled to one another.

This achieves the advantage that a deflection and control of the pressure loss of the fluid ducts and the corresponding cooling system can be easily effected by appropriately designed stator lamination groups. Additional components for deflecting the cooling fluid can thus be omitted. As a result, the number of components of the stator and the cost of its production can be reduced. A core idea of the invention is, among other things, to map the course of the cooling channel completely or at least partially in the laminated core. The necessary deflections, which previously had to be implemented using separate components, are also implemented in the laminated core of the stator.

The two stator sheet metal groups have different sheet metal geometries, which are arranged in axial layers in such a way that cooling channels, including a deflection of the cooling fluid, can be formed in the stator body. For this purpose, different sheet metal sections are used in the stator sheet metal groups. The sheet metal sections can be cut, for example, with a stamping tool with controlled punches, as a result of which the stator sheet metal groups can be produced in a particularly cost-effective manner. The fluid channels and/or the connecting channels are preferably designed as windows in the respective stator lamination group. The length or the axial extent of the fluid and/or connecting channels can be set and adjusted by lining up the stator lamination groups or the stator lamination sheets from which they are each formed.

Furthermore, the invention makes it possible to control the pressure loss via the number of stator laminations in the area of the deflection of the cooling fluid. As a result, the pressure loss along the cooling channel can be adjusted or reduced to a desired minimum. By changing the number of individual laminations in the outer groups, one of the outer groups of stator laminations, which implements the deflection of the cooling fluid in the stator body by means of the connecting ducts, the pressure loss along the fluid ducts can be changed or adjusted. In this case, for example, the pressure losses for the deflections of the cooling fluid can be set separately on the opposite end faces of the annular cylindrical stator body.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the set of claims, and particularly preferred configurations of the subject matter of the invention are described below.

The stator according to the invention is intended for use in an electrical machine. The electrical machine is used to convert electrical energy into mechanical energy and/or vice versa, and it generally includes the stationary part, referred to as the stator, stand or armature, and a part that is referred to as the rotor or rotor and is arranged such that it can move, in particular rotate, relative to the stationary part. In particular, the electric machine is dimensioned in such a way that vehicle speeds of more than 50 km/h, preferably more than 80 km/h and in particular more than 100 km/h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW and in particular more than 70 kW. Furthermore, it is preferred that the electrical machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.

For the purposes of this application, motor vehicles are land vehicles that are moved by machine power without being tied to railroad tracks. A motor vehicle can, for example, be selected from the group of passenger cars gen (passenger car), truck (lorry), moped, light motor vehicle, motorcycle, bus (COM) or towing vehicle.

The stator according to the invention can preferably be configured for a radial flux machine. The stator of a radial flow machine is usually constructed cylindrically or in the form of a cylindrical ring and generally consists of a stator body which is formed by electrical laminations which are electrically insulated from one another and are constructed in layers and packaged to form laminated cores. This structure keeps the eddy currents in the stator caused by the stator field low. Distributed over the circumference, grooves or peripherally closed recesses are let into the electrical lamination running parallel to the rotor shaft and accommodate the stator winding or parts of the stator winding. Depending on the construction towards the surface, the slots can be closed with locking elements such as locking wedges or covers or the like in order to prevent the stator winding from being detached.

The stator body is preferably designed in one piece. A one-piece stator body is characterized in that the entire stator body is formed in one piece, viewed circumferentially. The stator body is generally formed from a large number of stacked, laminated electrical laminations, each of the electrical laminations being closed to form a circular ring. The individual laminations can be held together in the stator body, for example, by gluing, welding or screwing.

According to an advantageous embodiment of the invention, provision can be made for the fluid channels to extend axially parallel to the axis of rotation of a rotor which is mounted so as to be rotatable with respect to the stator, which has proven to be advantageous in terms of cooling capacity and pressure loss.

According to a further preferred further development of the invention, it can also be provided that the first group of stator laminations is surrounded in the axial direction by two stator laminations of the first group of stator laminations. In this way, it can be achieved that the cooling fluid can be deflected at both end faces of the cylindrical ring-shaped stator body.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the axial extension of the first group of stator laminations corresponds to 3-10 times the axial extension of one of the second group of stator laminations, which has proven to be particularly advantageous with regard to the achievable cooling effect and the pressure loss.

According to a further particularly preferred embodiment of the invention, it can be provided that at least one end disk of the stator body is arranged axially on a second group of stator laminations such that at least one of the fluid channels and at least one connecting channel is closed in the axial direction. The lens can be formed in particular from a sheet metal or a plastic. The cover disk is particularly preferably a stator sheet metal.

Furthermore, the invention can also be further developed such that the lens has at least one supply channel, by means of which the hydraulic connection can be fluidically coupled to at least one of the fluid channels and/or connecting channels, which is particularly favorable hydraulically and in terms of connection technology.

In a likewise preferred embodiment variant of the invention, provision can also be made for a plurality of first groups of stator laminations to be arranged axially next to one another, as a result of which the length of the stator body can be adjusted.

It can also be advantageous to further develop the invention in such a way that the stator laminations of the first group of stator laminations and/or the stator laminations of the second group of stator laminations are formed essentially in the same parts, which is particularly advantageous in terms of production technology.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the first group of stator laminations and the second group of stator laminations define an essentially meandering flow path for the cooling fluid, which has also proven to be particularly advantageous in terms of cooling capacity and pressure loss.

In the stator or in the electrical machine, the cooling fluid has the function of dissipating heat as efficiently as possible from regions of the stator or of the electrical machine that are heating up and of avoiding undesired overheating of these regions. In addition to this main task, the cooling fluid can in particular also provide lubrication and corrosion protection for the moving parts and/or the metal surfaces of the cooling system of the stator or the electrical machine. In addition, it can in particular also remove contaminants (e.g. due to abrasion), water and air.

Finally, the invention can also be implemented in an advantageous manner such that the cooling fluid is a liquid, in particular a cooling oil. In principle, however, it is also think bar, aqueous cooling fluids, for example emulsions to use.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea.

• 1 einen Stator mit Lagerschilden in einer perspektivischen Ansicht,
• 2 einen Stator mit Lagerschilden in einer Explosionsdarstellung,
• 3 einen Stator mit freigestellten Fluidkanälen und Lagerschilden in einer Explosionsdarstellung,
• 4 eine Detailansicht eines Stators mit freigestellten Fluidkanälen in einer perspektivischen Ansicht,
• 5 eine Detailansicht eines Stators mit freigestellten, mäanderförmig verlaufenden Fluidkanälen in einer perspektivischen Ansicht.

It shows:

• 1 a stator with end shields in a perspective view,
• 2 a stator with end shields in an exploded view,
• 3 an exploded view of a stator with exposed fluid channels and end shields,
• 4 a detailed view of a stator with exposed fluid channels in a perspective view,
• 5 a detailed view of a stator with exposed, meandering fluid channels in a perspective view.

The 1 shows a stator 1 for an electrical machine, comprising a stator body 3, which is formed from a plurality of stator laminations 4 arranged in layers.

The stator body 3 has a plurality of fluid channels 5 through which a cooling fluid 6 can flow, as well as an A end shield 7 and a B end shield 8 which are each arranged on the end face and on opposite end faces 9 of the stator body 3 . How from the 2 As can be seen, the A end shield 7 has a hydraulic connection 10 by means of which the cooling fluid 6 can be guided through the A end shield 7 to at least one of the fluid channels 5 .

The stator body 3 is constructed from a first group of stator laminations 11, which has a plurality of fluid channels 12 extending essentially in the axial direction through the stator body 3, and a second group of stator laminations 13, which has a plurality of connecting channels 14 extending essentially in the circumferential direction through the stator body 3, by means of which two fluid channels 12 that are adjacent in the circumferential direction are fluidically coupled to one another. This can be seen particularly well from the detailed representation of the 5 comprehend.

The fluid channels 12 , which have a circumferentially closed contour, extend axially parallel to the axis of rotation of a rotor that is rotatably mounted relative to the stator 1 . To set the axial extension of the stator 1 or the axial extension of the fluid channels 12 over the entire axial length of the stator 1, if possible, a plurality of first groups of stator laminations 11 are arranged axially next to one another. It can be seen from the 5 furthermore that the first group of stator laminations 11 and the second group of stator laminations 13 define an essentially meandering flow path for the cooling fluid 6 . For this purpose, the first group of stator laminations 11 is bordered in the axial direction by two stator laminations 13 of the first group of stator laminations 13 . At least one closing disk 15 of the stator body 3 is also arranged axially on a second group of stator laminations 13 in such a way that at least one of the fluid channels 12 and at least one connecting channel 14 is closed in the axial direction.

In the 4 It is shown that the closing disk 15 has at least one supply channel 16, by means of which the hydraulic connection 10 can be fluidically coupled to at least one of the fluid channels 12 and/or connecting channels 14.

For this purpose, the connection 10 can widen in a funnel-like manner in the direction of the supply channels 16 in order to allow cooling fluid 6 to flow to a plurality of fluid channels 12 or connecting channels 14 .

This results in a cooling circuit that leads the cooling fluid 6 through the hydraulic connection 10 of the A end shield 7 to the supply channel 16 of the cover disk 15, from which the cooling fluid 6 is then meanderingly routed over almost the entire axial extent of the stator 1 through the fluid channels 12 and connecting channels 14. The cooling fluid 6 can then be led out of the stator 1 again at a suitable point.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

stator

3

stator body

4

stator laminations

5

fluid channels

6

cooling fluid

7

A bearing shield

8th

B end shield

9

end faces

10

hydraulic connection

11

stator laminations

12

fluid channels

13

stator laminations

14

connection channels

15

lens

16

feed channel

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3157138 A1 [0007]

Claims (10)

Stator (1) for an electrical machine, comprising a stator body (3) which is formed from a plurality of stator laminations (4) arranged in layers, and the stator body (3) has a plurality of fluid channels (5) through which a cooling fluid (6) can flow, and an A end shield (7) and a B end shield (8), which are each arranged on the end face and on opposite end faces (9) of the stator body (3), the A bearing shield (7) and/or the B end shield (8) and/or the stator body (3) have/has at least one hydraulic connection (10), by means of which the cooling fluid (6) can be guided through the A end shield (7) and/or the B end shield (8) and/or the stator body (3) to at least one of the fluid channels (5),characterizedthat the stator body (3) has a first group of stator laminations (11) which has a plurality of fluid channels (12) extending essentially in the axial direction through the stator body (3), and a second group of stator laminations (13) which has a plurality of connecting channels (14) which extend essentially in the circumferential direction through the stator body (3) and by means of which two fluid channels (12) which are adjacent in the circumferential direction are fluidically coupled to one another. Stator (1) after claim 1 , characterized in that the fluid channels (12) extend parallel to the axis of rotation of a rotatable to the stator (1) mounted rotor. Stator (1) according to one of the preceding claims, characterized in that the first group of stator laminations (11) is surrounded in the axial direction by two stator laminations (13) of the first group of stator laminations (13). Stator (1) according to one of the preceding claims, characterized in that the axial extent of the first group of stator laminations (11) corresponds to 3-10 times the axial extent of one of the second group of stator laminations (13). Stator (1) according to one of the preceding claims, characterized in that at least one closing disk (15) of the stator body (3) is arranged axially on a second group of stator laminations (13) in such a way that at least one of the fluid channels (12) and at least one connecting channel (14) is closed in the axial direction. Stator (1) after claim 5 , characterized in that the closing disk (15) has at least one supply channel (16) by means of which the hydraulic connection (10) can be fluidically coupled to at least one of the fluid channels (12) and/or connecting channels (14). Stator (1) according to one of the preceding claims, characterized in that a plurality of first groups of stator laminations (11) are arranged axially on one another. Stator (1) according to one of the preceding claims, characterized in that the stator laminations of the first group of stator laminations (11) and/or the stator laminations of the second group of stator laminations (13) are of essentially identical construction. Stator (1) according to one of the preceding claims, characterized in that the first group of stator laminations (11) and the second group of stator laminations (13) define an essentially meandering flow path for the cooling fluid (6). Stator (1) according to one of the preceding claims, characterized in that the cooling fluid (6) is a liquid, in particular a cooling oil.

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